Facebook is Quietly Blocking Ad Transparency Tools

Facebook has quietly made changes to its site that block tools developed to let the public see exactly how Facebook users are being targeted by advertisers, such as ProPublica, Mozilla and Who Targets Me.

Each tool stopped working this month after Facebook inserted code in its website that blocks them.

In a statement to ProPublica, Facebook said the change was meant to simply enforce its terms of service.

The latest move comes a few months after Facebook executives urged ProPublica to shut down its ad transparency project.